TheTVDb is rolling out some infrastructure changes today, which are currently having an impact on Infuse's ability to fetch metadata and artwork for TV shows.
You can keep an eye on the current status at: https://stats.fireco.re/
Hopefully everything will be back to normal soon.
Update 11/17 - Things are starting to come back online, but may not be 100% yet.
Update 11/18 - TV show fetching appears to be back to normal, and we're continuing to monitor for any further issues.
Update 11/18 9:04am - TV show fetching appears to be back to normal, and we're continuing to monitor the situation. If you are seeing any issues, please use the Edit option on the affected file(s) to refresh metadata and artwork for the entire series.
Update 11/18 10:21am - We're seeing a few lingering issues this morning, so we may not be out of the woods just yet.
Update 11/18 11:14am - We're seeing continued improvement. Some issues appear to be related to CDN caches, which should continue to update in the coming hours.
Update 11/26 - TheTVDB is looking into issues with incorrect season artwork.